[Mediawiki-l] New registrations

[Sandy Rozhon]

I've recently received email notification of a number of registration 
attempts -- all the user names have a name plus four digit number -- 
which I'm assuming are nothing more than spammers or malicious people 
attempting to login.   

However, when I look at the userlist, none of these usernames appear. 
 Where did they go?  Do they expire and automatically get removed if 
you don't elevate them to some user group?

I'm using v1.6.10

Sandy